1. Field of the Invention
The present invention relates to a method and a system for receiving radio stations, including at least one A/D converter, in order to digitize the entire desired frequency band, such as the FM band, received over at least one antenna.
2. Description of the Related Art
In FM radio receivers used these days, tuner assemblies are included which are suitable for filtering the HF signal, incoming at the antenna of the radio, amplifying it and mixing it to a suitable intermediate frequency, such as 10.7 MHz. This is followed either by an analog demodulation of the signal or the signal is digitized using an A/D converter and then digitally demodulated.
Thus, it is known, for example, from U.S. Pat. No. 6,334,051 B1 and published international patent application document WO 2009/021247 A1, that one may convert two or more radio signals A/D and select the respective required signal.
One disadvantage of the tuner assemblies known from the related art is that, before the digitization of the signal, its bandwidth is greatly reduced, so that to receive two or more signals, that is, two or more stations, one has to use a complete receiver path made up of a tuner assembly and A/D converter per signal to be received, respectively.
However, these days, especially in car radios, frequently two or more receiver paths are required, so as, in particular, to implement in one car radio important and desired functions, such as reception improvement by diversity algorithms, background tuners for RDS reception, the monitoring of TMC transmitters, etc.
This means that at least two receiver paths, made up in each case of a tuner assembly and an A/D converter are required. This represents a constructional increased cost that is not desirable.
In new system proposals it is provided that the entire FM band be digitized with the aid of a broadband A/D converter, so as to have the entire band present in digital form. Such a proposal can be gathered from published German patent application document DE 10 2008 012 127 A1, for instance. From this Laid-Open document, the A/D conversion of a whole broadcastband, such as AM or FM is known.
Moreover, a broadband receiver and a channel sampling method in mobile broadcasting are known from published German patent application document DE 698 37 941 T2. In this case, the A/D conversion of an entire reception band takes place and the channels used within a band are searched for, so as then to detect one channel with great rapidity.
Starting from this, the present invention is based on the object of achieving even better reception of radio stations in a method and a system for receiving radio stations of the type named at the outset.